Self-injections of medications have become increasingly common and various types of injection pens have been developed as a result.
While many types have been developed, generally, an injection pen comprises an injected dose adjusting knob and an injection unit. The injected dose adjusting knob is configured to adjust and set an injected dose of medication for the user.
The injection unit is configured to perform an injection according to the injected dose set by the injected dose adjusting knob by the user. For example, a common type of injection pen is an injection pen with a plunger, where the injection unit comprises a plunger which is configured to expel medication out of a needle for injection.
The user can set the amount of medication to be injected by rotating the adjusting knob to a predetermined graduation mark which corresponds to a change in the moving distance of the plunger. When a user presses the injected dose adjusting knob, the internal mechanisms of the injection devices press the plunger to a predetermined position for completing the injection of the set of amount of medication. These internal mechanisms vary among a number of alternative injection devices.
For disease management of a patient, it is critical that not only is a correct dose administered but that the correct dose is administered at a correct date and time.
For example, in a diabetic user, it is critical to inject insulin at a correct dose at a correct time.
In order to ensure the necessary effect of insulin, medical staff will encourage a patient with diabetes to record an injected dose and injection time for each injection.
However, the prior art injection device cannot record the injected dose and the injection time of the medication. The user is responsible for recording the injected dose of medication and the injection time in a notebook by handwriting or other record. If the user forgets to record the injection information or records the injection information incorrectly, the medical staff will have incorrect information for further diagnosis and treatment.
Some detection devices use a sensor to detect the moving distance of the plunger, and convert a detection result into electronic data.
In that approach, a computation result is directly affected by detection of the moving distance of the plunger and therefore the detection device requires high accuracy and requires complex operations, such that detection errors may occur. Additionally, a detection device for detecting the moving distance of the plunger must be integral to the injection device and thus increases the cost and complexity of the injection device.
There is a need for a detecting device and system that may be used with multiple different injection devices while accurately detecting the injected dose of the injection device.